Discovery News: Åk snabbare än ljuset
En intressant artikel jag blev tipsad om som förklarar en teori över hur man kan ta sig fram sig snabbare än ljuset.
Stå till, låt universum flytta sig. Allt som behövs är en warpmotor och lika mycket massa som Jupiter som bensin.
July 28, 2008 -- It is possible to travel faster than light. You just wouldn't travel faster than light.
Seems strange, but by manipulating extra dimensions with astronomical amounts of energy, two Baylor University physicists have outlined how a faster-than-light engine, or warp drive, could be created that would bend but not break the laws of physics.
"We think we can create an effective warp drive, based on general relatively and string theory," said Gerald Cleaver, coauthor of the paper that recently appeared on the preprint server ArXiv.org
The warp engine is based on a design first proposed in1994 by Michael Alcubierre. The Alcubierre drive, as it's known, involves expanding the fabric of space behind a ship into a bubble and shrinking space-time in front of the ship. The ship would rest in between the expanding and shrinking space-time, essentially surfing down the side of the bubble.
The tricky part is that the ship wouldn't actually move; space itself would move underneath the stationary spacecraft. A beam of light next to the ship would still zoom away, same as it always does, but a beam of light far from the ship would be left behind.
That means that the ship would arrive at its destination faster than a beam of light traveling the same distance, but without violating Einstein's relativity, which says that it would take an infinite amount of energy to accelerate an object with mass to the speed of light, since the ship itself isn't actually moving.
The fabric of space has moved faster than light before, says Cleaver, right after the Big Bang, when the universe expanded faster than the speed of light.
"We're recreating the inflationary period of the universe behind the ship," said Cleaver.
While the theory rests on relatively firm ground, the next question is how do you expand space behind the ship and contract it in front of the ship?
Cleaver and Richard Obousy, the other coauthor, propose manipulating the 11th dimension, a special theoretical construct of m-theory (the offspring of string theory), to create the bubble the ship would surf down.
If the 11th dimension could be shrunk behind the ship it would create a bubble of dark energy, the same dark energy that is causing the universe to speed up as time goes on. Expanding the 11th dimension in front of the ship would eventually cause it to decrease, although two separate steps are required.
Exactly how the 11th dimension would be expanded and shrunk is still unknown.
"These calculations are based on some arbitrary advance in technology or some alien technology that would let us manipulate the extra dimension," said Cleaver.
What the scientists were able to estimate was the amount of energy necessary, if the technology was available, to change these dimensions: about 10^45 joules.
"That's about the amount of energy you'd get if you converted the entire mass of Jupiter into pure energy via E = mc^2," said Cleaver, an energy far beyond anything humanity can currently envision creating.
While the challenges to creating a warp drive are quite formidable, the concept is intriguing, says Tufts University theoretical physicist Lawrence Ford.
"If there are extra dimensions and we could manipulate them, that would open up all sorts of exciting possibilities," said Ford.
"I don't see this leading immediately to a warp drive, but I could see it leading to other interesting possibilities in basic scientific research," said Ford.
Cleaver agrees that the creation of a real warp drive is still far away.
"Warp drive isn't doable now, and probably won't be for the next several millenia," said Cleaver.
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